1. Technical Field
The invention relates to a blast media and for the method of using the blast media for removing coatings such as paint, epoxy, polyurethane and similar materials from substrates. Even more particularly, the invention relates to a unique blast media formulation for removing coatings from aluminum and steel while preparing the underlying surface for subsequent new paint adhesion without damaging the surface.
2. Background Information
Various methods and blast media have been developed for stripping various types of coatings from an underlying metal substrate or composite substrate by various abrasives. These abrasives vary considerably in materials, sizes, grit, weight, etc., all of which are intended to achieve certain coating removal characteristics. These compositions contain particulates which are entrained in a pressurized fluid, generally air, and directed at predetermined pressures for impacting the particulates onto the coated surfaces for removing the coating therefrom without damaging the underlying surface.
It has been found that the removal of coatings on heavy steel substrates such as bridges, tanks, ships, etc. is more difficult than lighter coatings, especially where a subsequent profile is desired on the substrate for new paint adhesion. Also, it is desirable to be able to use a similar blast media for removing coatings from lighter substrates or surfaces such as aluminum, again without damaging the underlying surface and preparing the substrate for subsequent new paint adhesion. Some examples of prior art blast media and the method of using the media to strip coatings from substrates are found in U.S. Pat. Nos. 5,376,157, 5,439,493 and 5,509,971. These merely show various blast media formulations found suitable for certain applications.
The blast media of the present invention has been found to be extremely satisfactory for removing thick coatings on heavier steel substrates, as well as a less coarse blast media containing the same components as used in the more coarse blast media but in different percentages, for removing coatings from lighter substrates such as aluminum.
Prior art blast materials are usually designed to remove a certain type of coating from the substrate with other blast particles and materials being used to remove rust and corrosion from surfaces, that is, each of the particular blast components or particles are designed to achieve a certain end result. For example, one blast material removes the outer heavy coating and then another blast media is required to remove a thinner, intermediate coating and another media being used to remove rust and corrosion, with still another blast medium being used to prepare the surface for the subsequent adhesion of a new coating of paint. All of these require additional blasting steps, time and effort increasing the cost of a particular removal and surface preparation.